Centrifugally operated blade feathering device for propellers



s m L9 m P... o 03 C R1 A P MW FN %d J n Vi NF March 15, 1949.

CENTRIFUGALLY OPERATED BLADE FEATHERING I jkUMZO? W %km p Patented Mar. 15, 1949 UNITED STATES PATENT OFFICE CENTRIFUGALLY OPERATED BLADE FEATH- ERING DEVICE FOR PROPELLERS 3 Claims.

This invention relates to propellers for electric generators commonly known as wind electric devices.

Heretofore, devices have been utilized for varying the pitch of the blades of the propeller used to rotate the generator shaft.

The present invention relates to a propeller for a, wind electric machine which is so constructed that the pitch is automatically varied in proportion to the speed of rotation and the centrifugal force to which the blades are subjected. This change of pitch can be termed an automatic feathering action.

One of the objects of the invention is to provide an automatic feathering set of blades which are normally held in their usual operating position but will move outwardly in their supporting shafts against some yielding means as the speed and centrifugal force due to higher wind velocity or a reduction in mechanical load increases. The yielding means, of course, returns the blades to their normal operating position as the speed and centrifugal force decrease.

Another object of the invention is to provide a propeller of the type described above wherein the yielding means connected to the blades is so constructed that should one such yielding means for its blade become broken or should its connection with the blade become broken all of the blades will automatically feather causing a lower operating speed and thus preventing unbalanced rotation of the propeller shaft upon the disabling of one of the blades.

Another object of the invention is to provide a, propeller having blades which are capable of moving on their horizontal axes against the action of some yieldable means in addition to means for equalizing the amount of yieldable force exerted on all of the blades.

Still a further object of the invention is to provide linkage between the propeller hub unit and the propeller blades which will insure positive uniformity of pivotal movement of the blades as they are feathered under increasing centrifugal force.

These and other objects and advantages of the invention will more fully appear from the following description made in connection with the accompanying drawings, wherein like reference characters refer to the same parts throughout the views, and, in which:

Fig. 1 is a rear elevation of a propeller with portions broken away and other portions shown in dotted lines;

Fig. 2 is a section taken approximately on the line 22 of Fig. 1;

Fig. 3 is a perspective view of the equalizing plate.

Referring particularly to Fig. 2 there is shown a propeller shaft 4 having a tapered portion 5 upon which is mounted a hub unit indicated generally at B. The hub unit 6 has a rearwardly extending sleeve-like portion I mounted thereon, and the left-hand or rear end of said sleeve-like portion '1 is provided with a flange 3, The forward end of the propeller shaft is reduced and threaded as at 9 to receive an outwardly extending post member It, the latter acting as a nut to retain the hub unit 6 on the tapered portion 5 of the shaft 4. As shown in Fig. 1, the hub unit 6 is in the form of a spider, and said spider includes radiating web portions 6a.

Extending outwardly from the webs 6a in the hub 6 are rods I I upon which are slidably mounted propeller blades l2, said blades being socketed and provided with bearing sleeves l2a which are in contact with the radial rods H extending from the hub webs 6a.

Connected to each of the blades [2 is a tension spring IS, the connection being in the form of an anchor bolt 14. The springs I3 extend radially inwardly from their anchor bolts l4 and are secured to a plate [5 which is hereinafter referred to as an equalizing plate. Said plate l5 lies against the outer end of the post It) which, as stated above, extends outwardly from the end of the propeller shaft [4. It should be noted, however, that the equalizing plate !5 is not secured to the extended member or post H] in any way.

Mounted upon the sleeve-like rearward extension 1 of the hub unit 6 is a collar 1% which is provided with short radial arms l1. Mounted in the end of each of the arms I! is a spring socket generally indicated at l8. A side end portion of each arm 11 adjacent the spring socket I8 is provided with a tapered opening l9 to receive the ball-shaped end of a short arm 20 which is secured to a bracket 2| mounted on the end of each blade l2. The post 20 in each instance is secured to one side of the bottom portion of the blade, as best indicated in Fig. 1.

The tension springs l3 which are connected to the blades l2 and also to the equalizing plate 15 at the center of the unit and forwardly thereof are provided to maintain the blades at their normal working angle and to yieldably hold said blades in adjacent the hub unit 6. They do this in conjunction with the linkage comprising the collar l6, radial arms l1 and the short arms 20 which are connected to the blades. When the device is set up with the equalizing plate l5 lying against the outer end of the extension member H] on the outer end of the propeller shaft 4 the pull of the various springs l3 on their respective blades is equalized by reason or" the fact that the plate [5 will shift relative to the extended member l0 and thus balance the tensions of the spring.

When the apparatus attains suflicient speed and produces accompanying predetermined cen-.

trifugal force, the blades will tend to move outwardly on the posts H which extend from the hub units 6 and a pull will be exerted upon the posts 20, and ii and collar l6. Thebladesqwill thus be made to twist because of the linkage l1, 2% which will also move rearwardly with the collar IS, the latter twisting and sliding rearwardly on the rear sleeve-like extension I v. f t h,e ub unit 6. Because of this linkage, allofthefblades will twist or feather to the same degree. tinued outward movement of the-blades and further movement of the arms- 111 andrejarward movement of the collar [6 is prevented b y reas on of the flange 8 on the rear end of the sleeve like portion 1 of the hub lunit. This prevents the blades from assuming adead vcenter orover center position.

In addition to the .equalizingeffect of the disc 15 which connects with .the inner ends of the tension spring It the structure shown and described has another very important advantage. Should one of the springs 13 or its connecting bolt l4 become broken or one of the blade assemblies the tensionof the other two springs will pull the equalizing plate 15 from the forward end of the .extendedpost It] on the end of the propeller shaft 4, thus relieving tension on the two unbroken springs. As a result all three blades will automatically feather as they slide outwardly on their supporting rods ll, due to centrifugal force and the linkage I1, 20. This prevents any injury to the apparatus such as would happen if only one blade should become disconnected and feather leaving the other two in working condition and thus unbalancing the deviceto the extent that it might become seriously damaged.

While I have described theapparatus as being adapted for a wind electric machine or wind powered generator, it is, of course, to be understood that the propellerunit can be utilized for other purposes such as in ordinary windmillinstallations wherein the power is used to pump water.

,It will, of course, beunderstood that various lion.

What I claim is:

l. A centrifugally governed propeller for (wind ,electric machines and the like, comprising, a rotary hub unit, centrifugally governed propeller lades extending radially outwardly from said hub unit and mountedthereon for pivotal movements about their central longitudinal axes, and for longitudinal movements radially of said unit, an annular member mounted for oscillation and also longitudinal sliding .movement .on' ,said unit and carrying aseries :of circumferentially spaced, laterally extending ,ball sockets correisponding in number to said blades and directed generally towards said respective blades, each of said blades adjacent its inner end having an arm fixed thereto eccentrically of its longitudinal axis and adjacent its trailing edge and extended laterally toward one of said socket mem- .bers' and carryinga ball element connected with A changes may be made in the form, det ails, ar,-

its respective socket member and resilient means connected with said blades and exerting an inward longitudinal and radial pull thereon.

-2. ,A centrifugally governed propeller for a 5 wind-operated device comprising a rotary hub unit, a series of at least three centrifugally governed propeller blades extending radially outward in symmetrical arrangement from said unit and nountedthereon for pivotal movements about their central longitudinal axes and also for longitudinal-movements radially of said unit, an an- .nular membermounted for oscillation and also forlongitudinal sliding movement on said hub unit -and carrying a series of circumferentially spaced, universal connection elements corresponding in numberto said bladesand directed generally towards the inner end portions of s aid blades, each of said blade; adjacent its inner er d andtrailing edge having an arm connected there- ,totat a point eccentric to its longitudinal axis, said arms extending angularly of said blades towardsthe respective'universal connection ele- .ments ofrsaid annular member and each carryinga complementary universal connection element connected with its corresponding universal connection element on said annular member and .resilient means connectedwith said blades 5191' uniformly exerting inward, longitudinal ,pulls thereon.

3. Acentrifugally governed, propeller forwindoperated machines, comprising rotary hub unit, vprecisely three centrifugally governed propeller blades extending radially outward from said hub unit and mounted thereon for pivotal movements about their longitudinal center lines and for :longitudinal movements radially of said unit, an annular member mounted inwardly of said hub unit for oscillation and also longitudinal sliding movement on the inward portion of said unit if and carrying ata-radius somewhat greaterthan the maximum radius .of said hub unit, a series of three circumferentially spaced universal connection elements directed generally towards the inner ends of said respective blades,-each of said blades, adjacent itsinner end, having an ang-ulated arm.connected eccentrically of the longitudinal axis of said blade and adjace nt the traili ng edge thereofancl extending to the corresponding universal-connection element of said annular member and terminating in a complementaryuniversal connection element connected therewith and resilient means for uniformly exertingan inward pull upon said three blades.

J SE H- JA QBs- REFERENCES CITED Theiollowingreierences are of record in the :fileio thi mtsnb 430 UNITED STATES PATENTS runn a na lL h fi-i-tn- 3r ar en A r- 9.2.5 as 7 9 8 ev n .s p 6; 2 "1931, 710 Smith Oct; 24, 1,956,055 Wiegand Apr. 24, 1934 an e hit A 3, 

